To obtain satisfactory working properties and/or good product performance, it is common practice to introduce into aqueous cosmetic compositions water-immiscible ingredients, for instance fragrance, essential oils, lipophilic active agents, sunscreens or fatty substances.
However, due to their lipophilic nature, certain compounds are more or less difficult to dissolve in these formulations, and surface leaching may take place during storage. Such a phenomenon is undesirable from the point of view of stability of the formulation and/or with regard to consumer comfort insofar as it may destabilize the composition and/or affect the aesthetic appearance of the product (cloudy appearance) and/or give rise to unpleasant cosmetic results when applied to the skin and/or the hair; this phenomenon also limits the concentration of active agents in these formulations, which does not make it possible to obtain sufficiently effective products.
In order to dissolve and stabilize these lipophilic compounds, it is known practice to use oxyethylenated surfactants partly derived from petrochemistry (for example oxyethylenated hydrogenated castor oil).
However, consumers are increasingly in search of cosmetic products that are formed, totally or partly, from natural constituents or constituents of natural origin.
The term “natural compound” means a compound that is obtained directly from the earth or the soil, or from plants or animals, via, where appropriate, one or more physical processes, for instance grinding, refining, distillation, purification or filtration.
The term “compound of natural origin” means a natural compound that has undergone one or more additional chemical or industrial treatments, giving rise to modifications that do not affect the essential qualities of this compound and/or a compound predominantly comprising natural constituents that may or may not have undergone transformations as indicated above.
As non-limiting examples of additional chemical or industrial treatments giving rise to modifications that do not affect the essential qualities of a natural compound, mention may be made of those permitted by the control authorities such as Ecocert (Frame of reference for cosmetic, biological and ecological products, January 2003) or defined in manuals recognized in the field, such as the Cosmetics and Toiletries Magazine, 2005, vol. 120, 9:10.
There is thus still a need for a system for dissolving lipophilic compounds that is compatible with the formulation of “natural” or “bio-certified” cosmetic products, which allows these lipophilic compounds to be formulated without any concentration limit, so as to obtain stable, efficient formulations that are pleasant to use and that have an attractive aesthetic appearance, especially a clear, non-cloudy appearance. The inventor has discovered that a surfactant system comprising a combination of a fatty acid ester of sucrose and a fatty acid ester of polyglycerol can achieve the above objectives.